1. Field of the Invention
The present invention relates to an endoscope diagnostic apparatus which images self-fluorescence emitted from a self-fluorescent material included in a region (living body) to be observed of a subject to acquire a self-fluorescent image.
2. Description of the Related Art
An endoscope device which guides normal light (white light) emitted from a light source device to an endoscope tip portion, irradiates normal light onto a region to be observed of a subject, images reflected light to acquire a normal light image (white light image), and performs normal light observation (white light observation) has hitherto been used. Meanwhile, in recent years, an endoscope device which, in addition to normal light observation, irradiates excited light (special light) for self-fluorescent observation a region to be observed of a subject, images self-fluorescence emitted from a self-fluorescent material to acquire a self-fluorescent image (special light image), and performs self-fluorescent observation (special light observation) is utilized.
For example, JP2008-43383A describes an endoscope device which performs self-fluorescent observation.
JP2008-43383A describes a method in which, in a first fluorescence observation mode, three kinds of excited light are irradiated in order, and excited light is cut using an excited light cut filter provided on the front surface of a sensor to acquire a self-fluorescent image. The three kinds of excited light are different in wavelength, and the wavelength is optimized so as to capture self-fluorescent images of NADH, elastin, and collagen in which self-fluorescence intensity changes between a normal part and a lesion part.
In the first fluorescence observation mode, four fields are handled as one frame, and as shown in FIG. 9, white light, excited light 1, excited light 2, and excited light 3 are sequentially irradiated onto the subject in the respective fields of each frame. A normal light image is acquired by the sensor in the field 1, and subsequently, excited light is cut by the excited light cut filter and self-fluorescent images 1, 2, and 3 are sequentially acquired by the sensor in the fields 2 to 4. The motion images of the normal light image and the self-fluorescent images 1 to 3 are simultaneously displayed on a monitor.
JP2008-43383A describes a method in which, in a second fluorescence observation mode, two kinds of excited light 1 and 2 are irradiated in order, and these kinds of excited light 1 and 2 are cut using an excited light cut filter provided on the front surface of the sensor to acquire self-fluorescent images 1 and 2 of excited light 1 and 2, and to convert a site, at which a bright portion in the self-fluorescent image 1 and a dark portion in the self-fluorescent image 2 are aligned with each other, with a specific color to highlight a lesion part.
In the second fluorescence observation mode, two fields are handled as one frame, and as shown in FIG. 10, excited light 1 and excited light 2 are alternately irradiated onto the subject in the respective fields of each frame. In the fields 1 and 2, excited light is cut by the excited light cut filter, and self-fluorescent images 1 and 2 of excited light 1 and 2 are respectively acquired by the sensor. Then, the sites of a bright portion of the self-fluorescent image 1 and a dark portion of the self-fluorescent image 2 are extracted, and the extracted sites are displayed on the monitor with a specific color.